Selective capture of silver ions from aqueous solution by series of azole derivatives-functionalized silica nanosheets  

作　　者：Shanshan Mao Tao Shen Qing Zhao Tong Han Fan Ding Xin Jin Manglai Gao 

机构地区：[1]State Key Laboratory of Heavy Oil Processing,College of Science,China University of Petroleum,Beijing 102249,China [2]Unconventional Natural Gas Institute,China University of Petroleum,Beijing 102249,China

出　　处：《Chinese Journal of Chemical Engineering》2023年第5期319-328,共10页中国化学工程学报（英文版）

基　　金：the National Natural Science Foundation of China (21776306)。

摘　　要：The introduction of bifunctional groups into low-cost adsorbents for selective adsorption of Ag(I) through synergistic effect will have a profound impact on the recovery of precious metals. Organo silica nanosheets(organo-Si NSs) functionalized by series of azole derivatives(2-mercaptoimidazole(MI), 2-mercaptobenzimidazole(MBT) and 1H-1,2,4-triazole-3-thiol(MTT)), are fabricated and employed for selective removal of Ag(I). The structures of the organo-Si NSs are investigated using several characterization methods. The results of batch adsorption experiments display that the maximum adsorption amounts are 70.3, 103.2 and 139.5 mg·g^(-1) on MI-Si NSs, MBI-Si NSs and MTT-Si NSs for Ag(I) ions, and reach rapid equilibrium within 10–30 min. The adsorption processes are chemisorption and fit pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Notably, MTT-Si NSs is greatly selective for Ag(I) in multicomponent system, and the distribution coefficient value of Ag(I) ions reaches 2331.26 ml·g^(-1). The reusability of organo-Si NSs is verified by four cycles of regeneration tests with 0.1 mol·L^(-1) HNO_(3) as the eluent. A combination of experimental, structural along with theoretical analysis is conducted to proclaim the structure-adsorptivity relationship:(i) The adsorption mechanisms are attributed to complexation.(ii) The amino group and sulfhydryl group of MTT-Si NSs as well as MBISi NSs may have synergistic impacts on Ag(I) capture.(iii) The differences in adsorption behavior and selectivity of the three organo-Si NSs are mainly related to the form of function groups, charge density and steric hindrance of adsorbent. This work not only sheds light on the promise of functionalized organo-Si NSs for the rapid and selective removal/enrichment of Ag(I) ions in complex water systems,but also provides new insights for designing cost-effective Si NSs-based adsorbents.

关 键 词：Organo silica nanosheets Adsorption Silver ions SELECTIVITY Mechanism Waste treatment 

分 类 号：X703[环境科学与工程—环境工程] TQ424[化学工程]